Located outside the city of Prescott in the US state of Arizona, is a unique geological formation called Granite Dells, consisting of massive granite boulders that have eroded into rounded bumpy and unusual shapes giving the rocks a rippled appearance. The rocks formed 1.4 billion years ago at a depth of 2-3 km, before they were uncovered by weathering. By a process known as spheroidal weathering, common in granitic terrains, the rocks assumed rounded shapes and other unusual rock formations that characterize the Granite Dells.

Two very scenic artificial reservoirs — Watson Lake and Willow Lake — lie within the formation. The two lakes combined with numerous hiking trails offer a great place for boating, picnicking, hiking, and birding.